Telegraph system



1,545,602 L.M.POTT$ TELEGRAPH SYSTEM July 14, 1925.

Filed Dec. 18. 1922 mvenior: Lou/s M Poi/s Patented July 14, 1925.

UNITED 'STATES PATENT- OFFICE.

LOUIS M. POTTS, 0F HIGHWOOD, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed December 18, 1922. Serial No. 607,523.

To all whom it may concern: 7

Be it known that L'LOUIS M. Po'r rs, a

citizen of the United States of America, re-

siding at Highwood, in the county of Ber gen, State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telegraph systems, and particularly to current impulse repeaters for repeatingimpulses from one. line section to another.

The object of the invention is a repeating means which is eflicient, reliable and inexpensive, and which repeats the signaling impulses from one line section to another 'free from bias and distortion.

According to the preferredform of the invention, thereis provided a repeater consisting of a plurality of relays which respond to incoming signal current impulses for impressing on an adjoining line section impulses in accordance with those originally transmitted. To prevent mutilation of the signal impulses, predetermined onesof the relays are controlled jointly by the incoming signal current impulses and a current produced by an oscillating circuit which is arranged to operate at a frequency twice that or the incoming signal current impulses and which is capable of having its period varied on each current reversal for o crating said relays in synchronism with t e incoming signal current impulses. I A hetter understanding of the invention may he had from the following description, taken in conjunction with the accompanying drawing, which illustrates one embodiment of the invention. Fig. 1 illustrates the invention as applied to a particular circuit while Fig. 2 shows the curve characteristic of the current in a portion of the circuit.

Referring to the drawing, there is shown a pair of line sections 5 and 6 which extend from! distant stations and terminate at a repeating station A. It is understood, of course, that suitable transmitting and receiving mechanisms are associated at the terminating ends of each of the line sections 5. and'tl. At the repeating'station there is arran ged regenerative repeating means, thatis, means for repeating the impulsesfrom one line section to another as transmitted from the remote stations free from bias and distortion. The repeating means at the station A comprises a plurality of control relays, the operation of which are under the control of an oscillating circuit arranged to be controlled by the signals transmitted over the line sections. In systems wherein regenerative repeating means is employed, it is necessary that the repeating apparatus op? erate in synchronism with the transmitting apparatus of one of the stations so that the relays which control the application of current impulses to the adjoining linesection will operate at the proper moment, that is, the moment that the signals are received at the repeating station.

The line section 5 terminates at the repeating station A in a pair of ratio arms in which there is included the windings of a lays 10 and 11 will be operated in synchronism with the incoming impulses, an oscillating circuit com rising a condenser 15, an inductance 16 and an auxiliary condenser 17 is arranged in operative relation to a relay 18. Relay 18 controls-through its contacts a pair of relays 20 and 21, the formerhaving its armature connected to the armature of leak relay 8 so that the period of 0s cillation of the oscillating circult may he varied hy the insertion of the condenser 17 in parallel with the condenser 15, which has a capacity higher than that of condenser 17'.

The connection of thecondenser 17 in parallel with the condenser 15 is controlled by a polarized relay 22, which has its windlngs connected to contacts controlled loy relay 20. Connected to the armature of relay 21 is a condenser 23, I which is charged through contactscontr'olled by relay 24 and allowed to discharge upon the reversal of the position of the armature of relay 21 through the windings of relays 24, 25, 26, 27 and 28. Thus, upon the dlscharge of this condenser,

the previously enumerated relays are caused to reverse the position of their armatures for performing certain prescribed functions, relays 25 and .26-being arranged to control the application of a source of current to the apex of the ratio arms in which the line 6 terminates as determined by the energization of relay 9, while relays 27 and 28 control through their contacts the charging of condensers 29 and 30, respectively, which subsequent to their charging dis charge through, the windings of relays 31 and 32. Relays 31 and 32, like relays and 26, control through their contacts the application of a source of current to the apex of the ratio arms in which the line 5 terminates and which include the windings of receiving relay 7 Like in the previous case, the ratio arms in which the line 6 terminates have included therein the windings of a receiving relay35, which controls the ener ization of a relay 36. The latter relay, whidli has positive and negative current associated with its contacts, controls the energization of a pair of transmitting relays 37 and 38 as determined'by the position of the armature of relay 32.

In order that the relays which control the operation of other relays for impressing on the adjoining line sections impulses in accordance with those originally transmitted, the values of the inductance arranged in the oscillating circuit are such that the oscillations produced are equal to twice the frequency at which the line signals are transmitted. With the relay 18 operating at a frequency twice that of the line signals, the relays 25 and 26 and other relays controlled in the same circuit will operate at half the frequency of the oscillating circuit or at a frequency equal to the frequency at which signals are transmitted over the respective line sections. To avoid the use of two oscillating circuits when messagesare transmitted over the line sections in opposite directions simultaneously, adjustable inductances 39 and 40 are associated with the windings of control relays 31 and 32. The adjustment of the inductances 39 and 40 being suchthat the variation of one causes a' corresponding variation in the other, the current produced by the discharge of the associated condensers 29v and 30 may be regulated so cause the lag is determined by the period of the oscillating circuit rather than by usual method of delaying the rise of the current to anloperating value by the use of choke 001 s. the contacts controlled by relays 27. and 28 and the charge and discharge of condensers 29 and 30, relays 31 and 32 are caused to vibrate at the same frequency as relays 25 and 26, but witha different phase depending on the values of condensers 29 and 30 and inductances 39 and 40.

It is thought that a better understanding of the invention may be taken from the following detailed description. Assume for the purpose of illustration that impulses are being transmitted over the line section 5. Further assume that a positive impulse.

is transmitted followed by a negative 1mpulse. The passage of a positive impulse through the windings of relay 7 to the artificial line AL causes the reversal of the armature of this relay. .The armature of relay being reversed, current of a negative polarity is allowed to pass through the lower windings of relays 8 and 9 to the positir e terminal of the battery. However, before these relays reverse the position of their armatures, a momentary negative impulse is impressed through the right hand winding of relay 22, the circuit of which may be traced from negative battery, armature and lower. contact of relay 7, lower contact and arma-- 'ture of relay 8, conductor 41, armature and right hand contact of relay 20 and the right hand winding of .relay 22 to the positive source of battery. Relay 22, which has already attracted its armature so that con tact 42 is now closed connects the condenser 17 in'parallel with the condenser 15. Accordingly, relays 20 and 21 continue to operate at the frequency determined by the oscillating circuit, the condenser 15 eing now in parallel with the condenser 17 so that the frequency of oscillation is slightly less than the frequency of normal operation. Relay 9 in reversing the position of its armature impresses on the windings of re lay 10 a positive impulse, whereupon relay Due to the opening and closure of 10 is caused to reverse the position of its H armature connecting the positive source of battery with the upper contactof relay 26. Inasmuch as relays 24, 25 and 26 are controlled by the discharge of condenser 23 which in turn is controlled by relay 21, the operation of which is under the direct control of the oscillating circuit, or specifically, relay 18, these relays operate in synchronism or at a frequency equal to that at which the impulses are being transmitted "1,:v overthe line section 5. Accordingly, at the time relay 10 reverses the osition of its armature to connect the positive source of battery with the upper contact of relay 2 6,

the armature of relay 26 has been ppsitioned to engage its contact. Thus, an impulse of positive polarity Will be impressed on the line section 6, the ratio arms of which inverse the position of its armature, or the poreceived sition shown in the drawing, for likewise causing the operation of relays 8 and 9. However, before relays 8 and 9 reversethe position of their armatures, a negative impulse is impressed on the line conductor -11 which extends to the armature of relay 20. Now if relay 20 is in a position such that its armature engages at this moment its left hand contact, relayz22 will be caused to reverse the position of its armature, thus disconnecting the condenser 17 and allowing the oscillating circuit to operate at a frequency equal to that of normal. With condenser 17 connected in parallel. withcon denser 15, the circuit will oscillate at a frequency slightly below the frequency of the line signals. While with the condenser disconnected the circuit will oscillate at a frequency slightly higher than the frequency of the line signals.

. Likewise, relays 24, 25 and '26 are caused to reverse the position of their armatures to control the application of a corresponding source of current to the apex of the ratio arms in which the line section 6 terminates.

As previously stated, relays 10 and 11 are controlled jointly by relays 9 and 25. Since relay 25 is, through the instrumentality of the oscillating circuit, caused to operate at a frequency equal to that of the incoming impulses, one or the-other of the relays 19 or 11, depending upon the position of the armature 25, will be energized. Relay '11 may accordingly be operated for position-- ing its armature to the position shown in the drawing. Relay 26 being at this moment energized such that its armature engages its lower contact for impressing on the line section 6 a negative impulse or an impulse of a polarity corresponding to that originally transmitted over the line section 5.

Impulses impressed on the line conductor 6 from the station to which this line extends, pass through the windings of receiving relay 35 for causing the operation of this relay in accordance with thecharacter of the impulses. Relay 35 controls through its contacts the energization of relay 36. This 'latter relay, as previously stated, controls jointly with relay 32 the "energization of transmitting relays 37 and 38. Now, since relays 31 and 32 are under the control of the oscillating circuit, impulses transmitted over the line section. 6 will'be im ressed on the line section 5 in the same or er in which they were originally trans mitted. Relays 27 and 28 being included serially with relays 24, 25 and 26, alternately permit the charging and discharging of condensers 29 and 30, respectively. For example, when thearmature of relay 28 is in contact with its right hand contact, condenser 30 is charged positively. When the armature of relay28 is not in this position, the condenser 29 associated with the armature of relay 27 having been previously charged with a negative impulse, isallowed to discharge through the inductance 39 and 1 the left hand windings of relays 31 and 32 Inatures upon the application of the nega tive portion b-c of the discharge current characteristic as shown in Fig. 2. 1

When signals are impressed on line section 6 to be repeated to line section 5 through the action of relays 31, 32, 37 and 38, the

operation of the two former relays must-be in *phase with such signals. To provide for this condition, the inductances 39 and 40 are ,made' variable whereby the moment of operation of the relays will coincide with the signals impressed on line section 6. Accordingly,,the signals will be repeated to line section 5 in the same order as received at the repeating station and will be free from bias and distortion.

It is obvious from the previous description that the present invention provides a regenerative repeating means which is inexpensive and which does not require frequent readjustment. It is understood, of course, that although the invention has been disclosed as applied to a particular type-of system, variations may be made without de-. parting from the spirit and scope of the present invention.

v The invention claimed is:

1. In combination, a pair of iine sections, repeating means intermediate suchline sections comprising a lurality of ,electro-responsive evices, a c osed oscillatory circuit including inductance and capacityunder the control of impulses over said line sections, and means controlled by said oscillatory circuit for causin the operation of said electro-responsive evices and in consequence thereof the impression on the adjoining linesection of impulses in accordance with those transmitted over the other line section.

trolling the operation of said relays, and

means responsive to current impulses for regulating the period of said oscillating Circuit.

3. In combination two line sections terminating at'a repeating station Where repeating means is located, said repeating means comprising a plurality of relays, an oscillating circuit having a natural period,

I 10 means for causing said circuit to oscillate at ing station comprising a plurality of relays,

an oscillating circuit, means controlled by said circuit for controlling the operation of said relays, and means controlled jointly by q the incoming impulses and said relays for impressing on the adjoining line section impulses WlllCllv are free from bias and distor- -tion as determined by such inc'oming impulses.

5. In a telegraph system, two line sections extending from distant stations to a repeating station, each of said line sections being equipped for duplex service, repeating means at said repeating station comprising a plurality of relays, an oscillating circuit, means controlled by said oscillating circuit for controlling the operation of said relays, and

means controlled jointly by incoming impulses on each of said line sections and said relays for impressing simultaneously on the ad oining line sections impulses W 10h are free from bias and distortion as determined by the incoming impulses on said line sections:

6. Repeating means comprising a plurality of relays, an oscillating circuit having a natural period, means controlled by said oscillating circuit for controlling said relays, a condenser, and means responsive to signal current impulses for connecting said con? denser in operative relation with said oscillating circuit to vary its period.

7. In a repeater, an oscillating contact, a second contact, a condenser, means to charge and discharge said condenser in reverse di rections for succeeding cycles of the operation of said oscillating contact, and means to operate said second mentioned contact at half the frequency of operation of said oscillating contact under the control of said con- 'contact at the same frequency as the first mentioned oscillating contact but with a phase relation to the first mentioned contact controlled by the frequency of the oscillat- 4 ing circuit.

9. In. a repeater, an oscillatlng contact, an oscillating circuit, a second-contact, means to oscillate the second mentloned contact at the same frequency as the first mentioned contact, and means to adjust the phase relation of the oscillations of the two contacts by adjusting the frequency of the oscillating c rcuit.

In Witness whereof, I hereunto subscribe my name this 15th day of December A. D., 1922.

LOUIS M. POTTS. 

